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low idle but high when moving


Rushman04

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hey i got a 92 grand prix with a 3.1 in it and i had a prolem last week with the coils arcing. I changed the spark plug wires and that didn't work. So i got msd direct replacement coils for it. I put in three new ones. It still was runinng funny. The car at a stop light or when parked it idles at 500 and very rough but when you give it a little gas it goes right up to about 2 grand. When iam at 45 i can just take my foot off the accel. and curise.It stay up at 2 grand when driving even with no gas pedal. I have cleaned the throttle body and iac passages. Please help me i want to go driving its been a week since my car has been out.

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hmmm...

Does it do the same thing if you give it gas while in park or only while moving?

 

Could it be trickle down from worn out injectors?

Or perhaps high fuel pressure? Have you checked to make sure that all your vacuum lines are good? make sure the line is connected to your fuel regulator, even unhook and block the vacuum with your finger while the car is running and see what happens.

 

One thing that need regular cleaning on these motors is the port for the egr, although I doubt it's responsible for your problem. (I like to clean it with a top post battery brush)

 

Do you have a check engine light on?

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its only when iam in drive but also if iam driving then put it in Netural it goes up to 2500 for a little then drop to 500. Iam really getting sick of gm poorly built motors. the only one they built right was the 3.8 and the v8s

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Sick of poorly built? not the 3.1! I've had ten of them! Pushrod Power! The only bad one was one I bought bad because the motor was run without oil. 205000 on my best one and it runs like a freaking top.

now... stay away from dem 4 cylinders, ha hear! dem 6 are good!

click this link to see how far a good 3.1 can go!

http://www.w-body.com/forum/viewtopic.php?t=36352&start=15

 

now that I'm through ranting... I know that the rpm is partially controlled by the car's computer, I recall reading that the idle rpm is supposed to be like 50 higher in gear than in neutral or park, to compensate for the added load of the tranny guts and stuff. I wonder if you may need a new tps(throttle position) sensor or cleaning of the ports around the throttle body.

does anyone else have any input?

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